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1

An analytical solution for dynamic response of water barrier subjected to strong shock waves caused by an underwater explosion to dams

Lu L., Zou D., Zhu Y., Dong Y., Zuo C., Wu Y.

Polish Maritime Research

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2017

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S 2

111--117

EN

Shock waves arriving at a dam site are close to plane waves when the center of an underwater explosion is far from the dam site. In general, the wave pressure is calculated with COLE empirical formula. The COLE formula is a negative exponential function with respect to time. In this paper, a new analytical solution algorithm is proposed, which does not require the use of step-by-step time integration. In Comparison with the step-by-step time integration, the proposed algorithm requires relatively less calculation and avoids high-frequency oscillation. Furthermore, the vertical upstream surface and the sloping upstream surface in two types of the dams are analyzed in this paper. The research results indicate that the analytical solution can be applied for a dam with a vertical upstream surface. However, because the upstream face of a dam is inclined, the analytical solution can be obtained only for dams that are at lower height. Whenever the height of a dam is higher, then no analytical solution can be obtained, and only the use of step-by-step time integration can obtain a solution.

2

Sound power radiated from rectangular plates

Zou D., Crocker M. J.

Archives of Acoustics

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2009

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Vol. 34, No. 1

25-39

EN

An equation for calculating the sound power radiated from a rectangular plate with arbitrary boundary conditions is derived, in which the sound power radiated from the plate is represented in terms of the normal velocity distribution on the plate and a coupling matrix. The velocity distribution on the plate is expressed in terms of the modal amplitudes and normal modes. The coupling matrix for arbitrary boundary conditions is developed mathematically using the Rayleigh integral. Finally, an approach to compute the radiation efficiency for modes of vibration is presented and the radiation efficiency of the first four most efficient vibration modes for six different boundary conditions is presented.

3

Response of a plate to PZT actuators

Zou D., Crocker M. J.

Archives of Acoustics

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2009

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Vol. 34, No. 1

13-23

EN

In this paper, the response of a plate with arbitrary boundary conditions to PZT actuators is derived. It is assumed that the plate and the actuators are rectangular and the edges of the PZT actuators are parallel to the respective edges of the plate. The response of the plate is decomposed into normal modes. The modal amplitude of the normal mode is represented in terms of the shape function of the actuator and the normal mode. The shape function of the actuator is given as a~singularity function. The normal modes for the boundary conditions with which we are concerned are calculated based on theoretical analyses of Magrab. The results of this paper are useful in designing an active noise control system in which the PZT actuators are used as the control sources.